LINK<\/strong><\/a><\/p>\n\n\n\n“Due to their common occurrence in various types of chondrites, igneous rims formed on pre-existing chondrules throughout chondrule-forming regions of the solar nebula. Although the peak temperatures are thought to reach similar values to those achieved during chondrule formation events, the heating duration in chondrule rim formation has not been well defined. We determined the two-dimensional chemical and oxygen isotopic distributions in an igneous rim of a chondrule within the Northwest Africa 3118 CV3oxA chondrite with sub-micrometer resolution using secondary ion mass spectrometry and scanning electron microscopy. The igneous rim experienced aqueous alteration on the CV parent body. The aqueous alteration resulted in precipitation of the secondary FeO-rich olivine (Fa40\u201549) and slightly disturbed the Fe-Mg distribution in the MgO-rich olivine phenocrysts (Fa11\u201522) at about a 1\u2009\u00b5m scale. However, no oxygen isotopic disturbances were observed at a scale greater than 100\u2009nm. The MgO-rich olivine, a primary phase of igneous rim formation, has \u03b417O = \u20156\u2009\u00b1\u20093\u2030 and \u03b418O = \u20151\u2009\u00b1\u20094 \u2030, and some grains contain extreme 16O-rich areas (\u03b417O,\u25a1\u03b418O = \u02dc\u201530\u2030) nearly 10\u2009\u00b5m across. We detected oxygen isotopic migration of approximately 1\u2009\u00b5m at the boundaries of the extreme 16O-rich areas. Using oxygen self-diffusivity in olivine, the heating time of the igneous rim formation could have continued from several hours to several days at near liquidus temperatures (\u02dc2000\u2009K) in the solar nebula suggesting that the rim formed by a similar flash heating event that formed the chondrules.”<\/p>\n","protected":false},"excerpt":{"rendered":"
Nozomi Matsuda, Naoya Sakamoto, Shogo Tachibana, Hisayoshi Yurimoto Geochemistry Available online 10 August 2019 LINK “Due to their common occurrence in various types of chondrites, igneous rims formed on pre-existing chondrules throughout chondrule-forming regions of…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[61,9,56,148,14,20,65],"tags":[1842,3273,1839,1864,5137,4633,147,1845],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20266"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=20266"}],"version-history":[{"count":3,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20266\/revisions"}],"predecessor-version":[{"id":20269,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/20266\/revisions\/20269"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=20266"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=20266"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=20266"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}